A Simple SN2 Reaction for the Undergraduate Organic Laboratory

Esteb, John J.; Magers, John R.; McNulty, LuAnne M.; Morgan, Paul; Wilson, Anne M.

doi:10.1021/ed086p850

Cited by 13 publications

(14 citation statements)

References 5 publications

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“…Examples of kinetic studies of second-order reactions are abundant [35][36][37][38][39], for example, the bimolecular nucleophilic substitution (S N 2, or alternatively A N D N mechanism) reaction between pyridine and ethyl iodide (Scheme 3) [40]. Figure 3 shows the disappearance of the reagents and the formation of the pyridinium salt, as well as the result of attempting to fit the data using the first-order kinetic model (ln[py] vs time plot) or using the (adequate) second-order model (1/[py] vs time).…”

Section: Second-order Reactionsmentioning

confidence: 99%

Practical Chemical Kinetics in Solution

Seoud

Baader

Bastos

2016

Encyclopedia of Physical Organic Chemistry, 5 Volume Set

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Section: Second-order Reactionsmentioning

confidence: 99%

Practical Chemical Kinetics in Solution

Seoud

Baader

Bastos

2016

Encyclopedia of Physical Organic Chemistry, 5 Volume Set

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“…Reactions of competitive nucleophiles are very useful exercises for teaching nucleophilic substitution reactions (S N 1 and/or S N 2) at the undergraduate level. − They often rely on the use of primary (1°), secondary (2°), and tertiary (3°) alcohols and several nucleophiles in order to study the different mechanisms involved in these reactions (Scheme ). These reactions, however, only have a limited number of suitable substrates as any alcohol larger than pentanol has a large number of isomers leading to more cumbersome reaction mixtures to analyze .…”

Section: Introductionmentioning

confidence: 99%

New Look at the Competitive Nucleophilic Substitution Reaction in the Pentanol Series

et al. 2021

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Substitution reactions of alcohols are some of the simplest experiments performed in undergraduate organic chemistry laboratory settings. However, the use of gas chromatography (GC) as an analytical tool for these reactions can be at times laborious and time-consuming. In this work, 1-pentanol, 2-pentanol, 3-pentanol, and 2-methyl-2-butanol were reacted with a 50/50 mixture of ammonium chloride− ammonium bromide in water to yield the corresponding alkyl bromide and alkyl chloride mixtures. Aliquots of the reaction mixture were analyzed using proton nuclear magnetic resonance ( 1 H NMR) spectroscopy and verified by GC. Secondary to secondary carbocation rearrangements were observed in the nucleophilic substitution reactions of 2-and 3-pentanol yielding a mixture of 2-and 3-substituted alkyl halides, while the primary and tertiary alcohols yielded the expected products. Students were assessed on their observations and explanations with the majority of them able to identify the correct reasoning for the alkyl halides mixture formation. 1 H NMR spectroscopy provided an inexpensive and quicker method to analyze the mixture and expose the students to the secondary to secondary carbocation rearrangement in the nucleophilic substitution reaction in the pentanol series.

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“…In this experiment, we determine the E a values of different NAS reactions using three different nucleophiles on a porphyrin dye. Other undergraduate NAS reactions are described that focus on the number, position, and nature of the electron-withdrawing groups, using varying experimental conditions and assays. − There are no experiments that both compare the E a of different nucleophiles, which gives insights into the mechanism, and use thin layer chromatography (TLC) as the analytical method. This lab experiment provides a basis to teach other concepts, such as nucleophile hardness and multistep reactions.…”

Section: Introductionmentioning

confidence: 99%

“…The activation energy for substitution depends heavily on the nature of the nucleophile. Most undergraduate experiments currently used in laboratories concentrate on the number, position, and nature of the electron-withdrawing groups as factors in the mechanism of NAS reactions. − Herein, through a combination of varying experimental conditions and visual techniques, students estimate relative activation energies for three different primary nucleophiles: butanethiol, butylamine, and butanol. A sample reaction mechanism is shown in Scheme .…”

Section: Introductionmentioning

confidence: 99%

Experimental Determination of Activation Energy of Nucleophilic Aromatic Substitution on Porphyrins

et al. 2017

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A physical organic chemistry experiment is described for second-year college students. Students performed nucleophilic aromatic substitution (NAS) reactions on 5,10,15,20-tetrakis(2,3,4,5,6-pentafluorophenyl)porphyrin (TPPF20) using three different nucleophiles. Substitution occurs preferentially at the 4-position (para) because it is thermodynamically favored, and the 2- and 6- (ortho) positions are kinetically disfavored because of steric interactions with the porphyrin ring. The activation energy depends heavily on the nucleophile. Open-source software (ImageJ from NIH) was used to quantify relative intensities of spots on a TLC plate obtained from different times and varying temperatures. These data were used to generate Arrhenius plots allowing students to determine relative activation energies for three different primary nucleophiles. The experiment was developed by 5 undergraduates and evaluated by 40 organic chemistry II students and 8 students in a physical chemistry laboratory. Students gained a deeper understanding of the relationships between the NAS mechanism, Arrhenius plots, and activation energy.

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A Simple SN2 Reaction for the Undergraduate Organic Laboratory

Cited by 13 publications

References 5 publications

Practical Chemical Kinetics in Solution

Practical Chemical Kinetics in Solution

New Look at the Competitive Nucleophilic Substitution Reaction in the Pentanol Series

Experimental Determination of Activation Energy of Nucleophilic Aromatic Substitution on Porphyrins

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